Downregulation of C3'H Gene in Rice Alters Cell Wall Structures

p‐Coumaroyl ester 3‐hydroxylase (C3ˊH) is a key enzyme involved in the synthesis of lignin, a major component in vascular plants' secondary cell walls. Although the crucial role of C3ˊH in have been investigated, there is limited information available for its role in monocotyledonous grass species. The team of Yuri Takeda from Kyoto University in Japan studied the effect of C3ˊH‐deficiency on the structure and properties of grass cell walls.

C3ˊH‐knockdown lines generated via RNAi gene silencing, with approximately 0.5% of the normal expression level, reached maturity and set seeds. Meanwhile, C3ˊH‐knockout rice mutants generated via CRISPR-Cas9 mutagenesis were severely dwarfed and sterile.

Analysis of the mature C3ˊH‐knockdown RNAi lines revealed that their lignin were enriched in p‐hydroxyphenyl (H) units and had reduced levels of the normally dominant guaiacyl (G) and syringyl (S) units. Suppression of C3ˊH also resulted in substantial reduction in cell wall cross‐linking. The C3ˊH‐suppressed rice exhibited enhanced biomass saccharification.

These data demonstrate that C3ˊH expression is an important determinant of lignin content and composition as well as the degree of cell wall cross‐linking.

For more information, read the article in The Plant Journal.